How Do Salivary Glands Work in the Human Body?
The largest gland in human body, most essential and the major are salivary glands. They secrete a major amount of saliva in our mouths. It is better if you know a little bit in detail about the salivary glands, which can help you to speak to your doctor about aspects of care and surgery treatments in case you have been diagnosed with salivary gland cancer. Through particular openings called ducts, the salivary glands empty the juice into your mouth. The main function of saliva is to help in acts of chewing and swallowing. Your throat and mouth can develop several types of infections which can be prevented by the help of saliva. Mainly there are two types of salivary glands known as the major and minor glands.
The Major Salivary Glands
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The most essential and largest gland in human body related to saliva is the major salivary glands. The maximum amount of saliva is produced by these glands of the body itself. The sublingual glands, the submandibular glands, and the parotid glands from the major salivary glands of our system. Now, let’s talk about each of these glands in detail and know the structure of salivary gland.
What are the Functionality of the Parotid Gland?
The location of the parotid glands is right in front of the ears and are essentially the largest salivary glands of our body. Close to your upper second molar, there is a duct that secretes the saliva produced in the parotid glands directly into the mouth. The deep lobe and the superficial lobe are the two different parts of a parotid gland. The facial nerve lies in between these two lobes. This novel is essential for your body as it controls the ability to smile, raise your eyebrows and close your eyes.
The main blood supplier of the neck and head region is the external carotid artery which is another critical structure that lies near the parotid glands. Even a branch of the jugular vein known as the retromandibular vein lies near the gland. Parotidectomy is the surgery performed to treat a tumour in the parotid gland. This surgery requires great precision as the surgeon needs to open up and perform the surgery near the essential structure of salivary gland and veins.
What Do You Mean By the Submandibular Gland?
Below the jaw, we have the submandibular gland, which is about the size of a walnut. There are places on the tongue from where saliva produced in these glands is secreted directly into the mouth through a duct of submandibular gland. This gland also has a deep lobe and the superficial lobe, just like the parotid gland. The marginal mandibular nerve, which helps you in smiling, is a nearby structure.
Other than that, the muscle which helps you to move your lower lip or the platysma muscle along with the lingual nerve, which allows you to feel all the sensation near your tongue, is located near these glands. A portion of your tongue that helps in swallowing and speech has restricted movements. These movements are allowed by the hypoglossal nerve, which is also located in the same region. The entire structure of salivary gland should be known to you, and nearby structures must be protected during treatment or surgery to avoid any unnecessary damage.
Role of the Sublingual Glands
These are the smallest in size amongst all the major salivary glands, as the rest form amongst the largest gland in human body related to saliva. Below either side of the tongue and under the mouth floor, we have these two almond-shaped structures located. These glands are usually safe from having any tumour or cancer. Malignancy in these glands is very rare, even in the case of tumours.
The Minor Salivary Glands
Throughout the aerodigestive tract and the mouth, there are hundreds and plenty of minor Salivary Glands secreting saliva. These glands are practically invisible without a microscope, unlike the major salivary glands, which are visible. Most of them are found in the face anatomy region like the mouth palate, roof, tongue area, and lining of the lips. The other areas are inside the nose, the cheeks, the voice box or larynx, and sinuses. Tumours in these minor salivary glands are pretty rare, but they are more open to cancers than tumours. Usually, it is the roof of the mouth where the minor salivary gland cancer begins.
FAQs on Salivary Glands: Functions and Importance
1. What are salivary glands and what is their primary role in the human body?
Salivary glands are exocrine glands located in and around the mouth that produce and secrete saliva. Their primary role is to initiate the process of digestion. Saliva moistens and lubricates food, making it easier to chew and swallow. It also contains enzymes, like salivary amylase, which begin the chemical breakdown of carbohydrates right in the oral cavity.
2. What are the three major pairs of salivary glands and their specific locations?
Humans have three major pairs of salivary glands, each with a distinct location:
- Parotid glands: These are the largest salivary glands and are located on the sides of the face, just in front of the ears.
- Submandibular glands: Located below the jawbone (mandible), these glands produce a mix of serous and mucous secretions.
- Sublingual glands: These are the smallest of the major glands and are situated on the floor of the mouth, directly under the tongue.
3. What are the main components of saliva and their functions?
Saliva is approximately 99% water, but the remaining 1% contains several crucial substances. The main components include:
- Electrolytes: Such as sodium, potassium, calcium, and chloride, which help maintain pH balance.
- Enzymes: Primarily salivary amylase (ptyalin) for carbohydrate digestion and lingual lipase for fat digestion.
- Mucin: A glycoprotein that lubricates food and protects the oral mucosa.
- Antibacterial Compounds: Including lysozyme and immunoglobulin A (IgA), which help control the microbial population in the mouth.
4. What is the specific function of the enzyme salivary amylase, also known as ptyalin?
The specific function of salivary amylase, or ptyalin, is to start the enzymatic digestion of starches. It acts on complex carbohydrates (polysaccharides) like starch and glycogen, breaking them down into simpler sugars like maltose. This process begins as soon as food is mixed with saliva in the mouth, marking the very first step of chemical digestion.
5. How is the secretion of saliva controlled in the body?
Saliva secretion is controlled entirely by the autonomic nervous system. The presence, sight, smell, or even the thought of food can trigger nerve impulses. The parasympathetic nervous system stimulates the glands to produce abundant, watery saliva to aid in digestion. Conversely, the sympathetic nervous system is activated during 'fight or flight' responses, leading to the secretion of a smaller amount of thick, viscous saliva, which is why your mouth may feel dry when you are nervous or frightened.
6. Why are there differences in the type of saliva produced by the parotid, submandibular, and sublingual glands?
The differences in saliva composition are due to the different types of secretory cells in each gland, catering to specific needs. The parotid gland primarily contains serous cells and produces a watery, enzyme-rich saliva ideal for digestion. The submandibular gland has a mix of serous and mucous cells, producing a slightly thicker fluid that both digests and lubricates. The sublingual gland is dominated by mucous cells, secreting a thick, viscous saliva that is excellent for lubrication and binding food into a bolus.
7. What would happen to the initial process of digestion if a person's salivary glands stopped functioning correctly?
If the salivary glands were to stop functioning, several problems would arise. Firstly, the initial chemical digestion of carbohydrates would not occur in the mouth, placing a greater burden on the pancreas and small intestine. Secondly, without the lubricating effect of saliva, chewing and swallowing food would become very difficult and painful (a condition known as dysphagia). The mouth would become dry (xerostomia), leading to an increased risk of dental caries, gum disease, and oral infections due to the loss of saliva's antibacterial properties.
8. Besides digestion, what are the other critical functions of saliva?
Beyond its role in digestion, saliva performs several other vital functions for oral health and overall well-being. It continuously cleanses the mouth, washing away food debris and preventing bacterial overgrowth. Its antibacterial components, like lysozyme, actively fight microbes. Saliva also acts as a solvent, dissolving food particles, which is necessary for them to be detected by the taste buds. Furthermore, it plays a crucial role in protecting teeth by neutralizing acids and providing calcium and phosphate for remineralization.
